The present invention relates to a disposable diaper having a mechanical fastening system.
Conventional disposable diapers are provided at transversely opposite side edges of a rear waist region of the diaper with a pair of tape fasteners for joining the side edges to transversely opposite side edges of a front waist region of the diaper. There are various types of tape fasteners used for the above purpose. For example, a tape fastener may comprise a base tape provided on its inner surface with an adhesive zone or a hook member adapted to be combined with a loop member to form a mechanical fastener. Disposable diapers are also known to have the side edges made of a plastic sheet, a nonwoven fabric or a laminate of a plastic sheet and a nonwoven fabric.
Disposable diapers provided with tape fasteners are usually supplied to consumers in the form of a package in which individual diapers are folded up with the tape fasteners folded back inwardly of the diapers and placed on the inner surfaces of the respective side edges of the diapers. In this manner, the adhesive zones and/or the hook elements of the fasteners can be protected from being contaminated by extraneous substances. Furthermore, the presence of the fasteners do not obstruct the diapers from being folded up. However, a serious problem should be encountered when the fasteners use hook members and the transversely opposite side edges of the diaper have their inner surfaces formed by plastic sheets. Specifically, it is impossible in such an arrangement to temporarily anchor the hook members to the foregoing inner surfaces and the fasteners may unintentionally shift to obstruct operation of folding up the diapers. Thus, extraneous substances may contaminate the inner surfaces of the fasteners.
In view of the problem as has been described above, it is an object of the present invention to provide a disposable diaper in which hook members employed in tape fasteners for the disposable diaper can be temporarily bonded to the inner surfaces of the diaper side edges.
According to the present invention, there is provided a disposable diaper comprising: a liquid-pervious topsheet, a liquid-impervious backsheet and a liquid-absorbent core disposed therebetween so as to form a first waist region, a second waist region and a crotch region extending therebetween; front surfaces in proximity of transversely opposite side edges of the first waist region including a release zone; the first waist region being provided on the transversely opposite side edges thereof with a pair of extensions; the extensions being provided on front surfaces thereof with hook members adapted to be engaged with loop members; the hook members having adhesive layers formed on front surfaces thereof; and the extensions being folded back inwardly of the diaper and peelably bonded to the release zones by the adhesive layers.
According to an embodiment of the present invention, the loop members are provided on a rear surface of the second waist region.
According to another embodiment of the present invention, the loop members are peelably engaged with the hook members on front surfaces of the loop members, the loop members being peelably bonded to the release layers by adhesive layers formed on rear surfaces of the loop members.
It should be noted here that the extensions, the hook members and the adhesive layers form tape fasteners.
In the disposable diaper according to the present invention, the presence of the tape fasteners does not obstruct the diaper from being rolled up for packaging or storage even when the tape fasteners use the hook members of a so-called mechanical fastener type. The reason for this is that each of the tape fasteners is provided on its inner surface with the adhesive layer by means of which the tape fastener can be temporarily bonded to the inner surface of the diaper.
In accordance with an aspect of the present invention, a disposable diaper is provided. The diaper has, in a longitudinal direction thereof, a front waist region, a rear second waist region and a crotch region extending therebetween. The diaper comprises a liquid-pervious topsheet; a liquid-impermeable backsheet extending transversely beyond a periphery of the top sheet in the rear waist region to form a pair of extended portions which define transversely opposite side edges of the rear waist region, respectively, wherein an outer surface of the backsheet defines an outer surface of the diaper, and an inner surface of the backsheet in the extended portions defines, together with an inner surface of the topsheet, an inner surface of the diaper; and a liquid-absorbent core disposed between the topsheet and backsheet. The diaper further comprises release zones defined solely by the inner surface of the backsheet in the extended portions, in proximity of the transversely opposite side edges of the rear waist region, respectively; and a pair of extensions provided on the transversely opposite side edges of the rear waist region, respectively. Hook members are provided on inner surfaces of the extensions, respectively. Adhesive layers are coated on inner surfaces of the hook members, respectively. The extensions, in a folded state, are folded back inwardly of the diaper and peelably bonded to the release zones by the adhesive layers, respectively. At least one loop member is provided on the outer surface of the diaper in the front waist region and adapted to be peelably engaged with the hook members. The backsheet is made of a plastic sheet.
Preferably, the hook members and the loop member constitute a mechanical fastener.
In accordance with another aspect of the present invention, a disposable diaper is provided. The disposable diaper has, in a longitudinal direction thereof, a front waist region, a rear second waist region and a crotch region extending therebetween. The diaper comprises a liquid-pervious topsheet; a liquid-impermeable backsheet extending transversely beyond a periphery of the top sheet in the rear waist region to form a pair of extended portions which define transversely opposite side edges of the rear waist region, respectively, wherein an outer surface of the backsheet defines an outer surface of the diaper, and an inner surface of the backsheet in the extended portions defines, together with an inner surface of the topsheet, an inner surface of the diaper; and a liquid-absorbent core disposed between the topsheet and backsheet. The diaper further comprises release zones defined by the inner surface of the backsheet in the extended portions, in proximity of the transversely opposite side edges of the rear waist region, respectively; and a pair of extensions provided on the transversely opposite side edges of the rear waist region, respectively. Hook members are provided on inner surfaces of the extensions, respectively. Adhesive layers are coated on inner surfaces of the hook members, respectively. The extensions, in a folded state, are folded back inwardly of the diaper and peelably bonded to the release zones by the adhesive layers, respectively. At least one loop member is provided on the outer surface of the diaper in the front waist region and adapted to be peelably engaged with the hook members. The backsheet includes a plastic sheet having an exposed surface defining the inner surface of the backsheet in the extended portions. The hook members have hooks mechanically engageable with loops of the loop member. The plastic sheet extends continuously uninterruptedly throughout the extended portions. The exposed surface of the plastic sheet defines the entire inner Surface of the backsheet in the extended portions, including the release zones.